Detect BSD as current OS

Summary:
Allow to fix paths according hier(7):

use Keruald\OmniTools\OS\CurrentOS;

if (CurrentOS::isBSD()) {
    $luaPath = "/usr/local/bin/lua54";
}

Test Plan: CurrentOS::isBSD() on a FreeBSD dev server

Reviewers: dereckson

Reviewed By: dereckson

Differential Revision: https://devcentral.nasqueron.org/D3024